Patient-Specific Alignment Guide For Multiple Incisions

ABSTRACT

A patient-specific alignment guide for an orthopedic implant. The alignment guide can include a body having first and second opposing surfaces, the second surface adapted for positioning over a skin surface, and at least one extension extending from the second surface body. The extension has a distal end defining a patient-specific end surface that is mateable in form-fitting manner with a subcutaneous portion of the patient&#39;s anatomy, and at least one guiding passage extending between the first surface of the body and the distal end of the extension.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in part of U.S. application Ser. No.11/756,057, filed on May 31, 2007, which claims the benefit of U.S.Provisional Application No. 60/812,694, filed on Jun. 9, 2006. Thisapplication claims the benefit of U.S. Provisional Application No.60/953,637, filed on Aug. 2, 2007. The disclosures of the aboveapplications are incorporated herein by reference.

INTRODUCTION

Various custom made, patient-specific orthopedic implants and associatedtemplates and guides are known in the art. Such implants and guides canbe developed using commercially available software. Custom implantguides are used to accurately place pins, guide bone cuts, and insertimplants during orthopedic procedures. The guides are made from apre-operative plan formed from an MRI or CT scan of the patient and relyon matching a subcutaneous anatomic feature for correct positioning.

The present teachings provide patient-specific guides for minimallyinvasive procedures.

SUMMARY

The present teachings provide a patient-specific alignment guide for anorthopedic implant. The patient-specific guide can include a body havingfirst and second opposing surfaces, the second surface adapted forpositioning over a skin surface, at least one extension extending fromthe second surface body, the extension having a distal end, the distalend defining a patient-specific end surface that is mateable inform-fitting manner with a subcutaneous portion of the patient'sanatomy, and at least one guiding passage extending between the firstsurface of the body and the distal end of the extension.

In another aspect, the patient-specific alignment guide can include abody having first and second opposing surfaces, the second surface forpositioning over the skin, and a plurality of extensions extending fromthe body, each extension having a distal end, at least one extensionhaving a distal end defining a patient-specific end surface that ismateable in form-fitting manner with a subcutaneous portion of thepatient's anatomy, the at least one extension having a longitudinalpassage communicating with the first surface of the body and extendingto the distal end of the at least one extension.

The present teachings also provide a method for multiple incisionorthopedic surgery. The method includes making a plurality of incisionsthrough the skin of the patient to a plurality of correspondingsubcutaneous anatomic portions, supporting a body of an alignment guideoutside the incisions, the alignment guide having a plurality ofextensions extending from the body of the alignment guide, andpercutaneously passing each extension through the correspondingincision, at least one extension having a patient-specific end surfaceconformable in form-fitting manner with a corresponding subcutaneousanatomic portion. The method further includes mating the end surface ofthe at least one extension to the corresponding subcutaneous anatomicportion, inserting a tool through a guiding passage extending from thebody and along the at least one extension to the distal end surface ofthe at least one extension, and preparing the corresponding subcutaneousanatomic portion for the surgical procedure.

Further areas of applicability of the present teachings will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is an isometric view of a patient-specific alignment guideaccording to the present teachings;

FIG. 1A is an environmental view of a patient-specific alignment guideaccording to the present teachings;

FIG. 2 is an environmental view of a patient-specific alignment guideaccording to the present teachings;

FIG. 3A is an environmental view of a patient-specific alignment guideaccording to the present teachings;

FIG. 3B is a view of the patient's anatomy after removal of thealignment guide of FIG. 3A; and

FIG. 4 is an environmental view of a patient-specific alignment guideaccording to the present teachings.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no wayintended to limit the teachings, its application, or uses. For example,although the present teachings are illustrated for specific implant oralignment guides in spinal surgery, the present teachings can be usedfor other guides, templates, jigs, drills, rasps or other instrumentsused in various orthopedic procedures.

The present teachings generally provide patient-specific implant guidesfor use in orthopedic surgery for the knee, hip, shoulder, or spine, forexample. The implant guides can be used either with conventional orpatient-specific implant components prepared with computer-assistedimage methods. Computer modeling for obtaining three dimensional imagesof the patient's anatomy using MRI or CT scans of the patient's anatomy,the patient specific prosthesis components, and the patient-specificguides and templates can be provided by various CAD programs and/orsoftware available, for example, by Materialise USA, Ann Arbor, Mich.

The guides are generally formed using computer modeling for matching athree-dimensional image of the patient's bone surface (with or withoutcartilage or other soft tissue), by the methods discussed above. Theguides can include custom-made guiding formations, such as, for example,bores or holes that can be used for supporting or guiding otherinstruments, such as drills, reamers, and cutters, or for inserting pinsor other fasteners. The guides can be use in minimally invasive surgery,and in particular in surgery with multiple minimally-invasive incisions.Only portions of the guide are inserted through the incisions, while themain body of the guide remains outside the incisions.

Referring to FIG. 1, a patient-specific alignment guide 100 includes abody 102 having first and second surfaces 106, 108, and one or moreextensions 104. Each extension 104 can extend from the body 102 away andspaced apart from the second surface 108, such that the extensions 104and the second surface define a void or empty space. Each extension 104can terminate at a distal end 120. Although four substantially parallelextensions 104 are illustrated in FIG. 1, fewer or additional extensions104 can be included. Each extension 104 can have a different orientationat an angle relative to the other extensions 104 and to the body. Theorientation of each extension 104 can be determined based onpatient-specific considerations, as discussed below.

Referring to FIG. 1A, the alignment guide 100 can include one or moreguiding passages 110, each guiding passage 110 corresponding to one ofthe extensions 104 and extending from the first surface 106 to thedistal end 120 of the corresponding extension 104. The guiding passage110 can be a longitudinal internal bore. The guiding passage 110 canalso be a longitudinal slot or other open channel formed on an outersurface of the extension 104. In one aspect, one or more the guidingpassages 110 can be in the form of a cutting slots. Similarly to theextensions 104, the guiding passages 110 can have differentorientations, such along axes A, A′, etc, relative to one another andrelative to the body 102. The orientations of the extensions 104, theguiding passages 110 and corresponding axes A, A′ can bepatient-specific, as determined by the corresponding geometricrelationship of subcutaneous anatomic portions 82 of the patient.Similarly, the length of each extension 104 and its correspondingpassage 110 can be different, as determined by the relative depths ofthe subcutaneous anatomic portions 82. In the exemplary alignment guideof FIG. 1A, two extensions 104 with different lengths L and L′corresponding to different depths d, d′ of the subcutaneous anatomicportions 82 are illustrated. The orientations and locations of theextensions 104 and the corresponding bores 110 can be determined duringpre-operative planning of the corresponding surgical procedure. In oneaspect, one or more extensions 104 can be pivotably or angulatablycoupled to the body 102, such that the orientation A of one or moreextensions 104 can be adjusted intra-operatively by the surgeon, asnecessary.

The guiding passages 110 can be sized and shaped to receive a tool 200,such as a drill bit of a drilling instrument, or other end tool that canbe used for preparing the surgical site, as shown in FIG. 1. The guidingpassages 110 can be cylindrical internal bores with variously shapedcross-sections, including circular, triangular, oval, polygonal,slot-like or otherwise shaped. The guiding passages 110 can also beslots or grooves or open channels defined on an outer surface of thecorresponding extensions. At least one distal end 120 can define apatient-specific distal end surface or footprint 122 that can conform ina form-fitting manner, mate and nest with a corresponding portion 82 ofthe patient's anatomy, as illustrated in FIG. 2. The footprint 122defines a three-dimensional patient-specific contour surface.Additionally, the position, dimensions, distances and orientations ofthe distal ends 120 relative to one another can be designed during thepre-operative planning procedure to conform or have a nesting surface tonest to a plurality of corresponding portions 82 of the patient'sanatomy. The subcutaneous anatomic portions 82 can be bone portions orother subcutaneous tissue accessible by corresponding minimally invasiveincisions 88.

In one aspect, each extension 104 can include a guiding passage 110 anda distal end with a patient-specific footprint 122. In another aspect,some of the extensions 104 can be used for stabilizing and anchoring thealignment guide 100 to the patient, and not for passing instrumentsand/or drilling therethrough. In this respect, such stabilizingextensions 104 may or may not include a guiding passage 110. Astabilizing extension may or may not have a patient-specific footprint122 at its distal end 120. For example, the distal end 120 of astabilizing extension 104 can have a tapering or pointed tip foranchoring. An alignment guide 100 having three or more extensions withonly one of the extensions 104 having a guiding passage 110 and apatient-specific foot print 122, can be used, for example, in anteriorcruciate ligament (ACL) replacement procedure.

As shown in FIG. 1, the extensions 104 can be integrally formedintegrally with the body 102, forming one monolithic, one-piece device.In one aspect, and referring to FIG. 1A, one or more extensions 104 canbe modular, such that one or more extensions 104 can be added or removedfrom the body 102 for a particular application. In another aspect, oneor more extensions 104 can be telescopically coupled to the body 102,such that the length of the extension 104 or the distance of the distalend 120 from the second surface 108 of the body 102 can be increased ordecreased to accommodate variations between similar subcutaneousanatomic features of the patient.

FIGS. 2 and 3 illustrate an exemplary alignment guide 100 for use in aspinal procedure. The alignment guide 100 can be used, for example, todrill holes 84 for fasteners or other implants in adjacent vertebrae ofthe spine 80. The exemplary alignment guide 100 can include four distalends 120 that can be used to drill two pairs of holes 84 atcorresponding portions 82 of the spine, for inserting pedicle screws orother fasteners for spinal fixation or other spinal procedure. The body102 of the alignment guide 100 can be positioned with the second surface108 of the body 102 on an outer surface or the skin 86 of the patient'sanatomy outside the incision. Each extension 104 can be percutaneouslyinserted through a corresponding minimally-invasive incision 88 andpositioned in nesting conformance with a subcutaneous portion 82 of thespine for which the patient specific footprint 122 of the extension 104was specifically designed to nest and conform in a form-fitting manner.After the alignment guide 100 is positioned on the patient's skin 86 andthe extensions 104 are percutaneously passed through correspondingincisions, such that each footprint 122 contacts and conforms in anesting manner to the corresponding subcutaneous anatomic portion 82 ofthe spine 80, a drill 200 or other instrument can be percutaneouslyinserted for preparing the subcutaneous anatomic portion 82 to receive afastener, an implant or a portion of an implant. The alignment guide 100can be secured on the patient with guide wires or drill bits othertemporary fasteners and supporting devices. In one aspect, a guide wirecan pass through a guiding passage 110, while another guiding passage isused for drilling.

FIG. 4 illustrates an exemplary alignment guide 100 for use with a longbone 90, such as a femoral bone, for a fracture or other traumaprocedure, in which an intramedullary nail 300 having a proximal portion302 and a distal portion 304 can be implanted. The alignment guide 100can be used to drill openings for securing first and second lockingfasteners 310 transversely through an intramedullary nail 300 from atrochanteric region 92 to the head 96 of the femoral bone 90. Thealignment guide 100 can have first and second extensions 104 havinglength, size and orientation determined such that their correspondingdistal ends 120 and foot print surfaces 122 conform to the subcutaneousanatomic portions of the femoral bone 90 at the site of the insertion ofthe fasteners 310, at the proximal portion 302 of the intramedullarynail 300. Another alignment guide 100 can be used, for example, fordrilling openings for fasteners 310 passing through the distal portion304 of the intramedullary nail 300, and adapted for that bone location.

It will be appreciated that other guides can be similarly constructedfor guiding and preparing other bones or bone joints for receivingprosthetic components or fixation pins or other fasteners, or forsecuring bone plates for fractures and other defects. Patient-specificalignment guides 100 can be constructed, for example, for variousportions of the spine, the wrist, long bones of the extremities, as wellas for various bone regions associated with joints, such as the knee,the hip, the shoulder, etc. The patient-specific alignment guides 100can include one or more guiding passages 110 along extensions 104 thatpass through minimally-invasive incisions and have patient-specific footprints that conform and nestingly mate with corresponding subcutaneousanatomic portions of a specific patient. It will be appreciated that thesubcutaneous anatomic portions 82 can include bone tissue or soft tissueassociated with underlying bone tissue. The body 102 of the alignmentguide 100 and access to the guiding passages 110 can remain outside theincisions 88, such that the incision size can be reduced, and thevarious tools and alignment guides 100 can be easily manipulated by thesurgeon outside the incisions.

The foregoing discussion discloses and describes merely exemplaryarrangements of the present teachings. One skilled in the art willreadily recognize from such discussion, and from the accompanyingdrawings that various changes, modifications and variations can be madetherein without departing from the spirit and scope of the teachings asdescribed herein.

1. A patient-specific alignment guide for orthopedic surgery comprising:a body having first and second opposing surfaces, the second surfaceadapted for positioning over a skin surface; at least one extensionextending from the second surface body, the extension having a distalend, the distal end defining a patient-specific end surface that ismateable in form-fitting manner with a subcutaneous portion of thepatient's anatomy; and at least one guiding passage extending betweenthe first surface of the body and the distal end of the extension. 2.The alignment guide of claim 1, wherein the extension is modularlycoupled to the body.
 3. The alignment guide of claim 1, wherein theextension is integral to the body forming one monolithic piece.
 4. Thealignment guide of claim 1, wherein the extension is telescopicallycoupled to the body.
 5. The alignment guide of claim 1, wherein theextension is pivotably coupled to the body.
 6. The alignment guide ofclaim 1, wherein the guiding passage is an internal bore passing throughthe extension.
 7. The alignment guide of claim 1, wherein the guidingpassage is an open channel along an outer surface of the extension. 8.The alignment guide of claim 1, wherein the guiding passage has aslot-like cross-section.
 9. The alignment guide of claim 1, wherein thedistal end of each extension defines a three-dimensionalpatient-specific contour.
 10. A patient-specific alignment guide fororthopedic surgery comprising: a body having first and second opposingsurfaces, the second surface for positioning over the skin; and aplurality of extensions extending from the body, each extension having adistal end, at least one extension having a distal end defining apatient-specific end surface that is mateable in form-fitting mannerwith a subcutaneous portion of the patient's anatomy, the at least oneextension having a longitudinal guiding passage communicating with thefirst surface of the body and extending to the distal end of the atleast one extension.
 11. The alignment guide of claim 10, wherein theguiding passage is aligned along a longitudinal axis and the orientationand position of the axis is patient-specific.
 12. The alignment guide ofclaim 10, wherein the orientation of the guiding passage can be changedintraoperatively.
 13. The alignment guide of claim 10, wherein the atleast one extension is telescopically coupled to the body.
 14. Thealignment guide of claim 10, wherein the subcutaneous anatomic portionis a vertebral portion.
 15. The alignment guide of claim 10, wherein thesubcutaneous anatomic portion is a long bone portion.
 16. The alignmentguide of claim 10, wherein the subcutaneous anatomic portion is asubcutaneous soft tissue portion overlying a bone portion.
 17. Thealignment guide of claim 10, wherein the extensions have differentlengths determined by the patient's anatomy.
 18. The alignment guide ofclaim 10, wherein each extension has a distal end defining apatient-specific end surface that is mateable in form-fitting mannerwith a subcutaneous portion of the patient's anatomy, and each extensionhas a longitudinal guiding passage communicating with the first surfaceof the body and extending to the distal end of the extension.
 19. Amethod for multiple incision orthopedic surgery comprising: making aplurality of incisions through the skin of the patient to a plurality ofcorresponding subcutaneous anatomic portions; supporting a body of analignment guide outside the incisions, the alignment guide having aplurality of extensions extending from the body of the alignment guide,wherein at least one extension has a patient-specific distal end surfaceconformable in form-fitting manner with a corresponding subcutaneousanatomic portion; percutaneously passing each extension through thecorresponding incision; mating the end surface of the at least oneextension to the corresponding subcutaneous anatomic portion; insertinga tool through a guiding passage extending from the body and along theat least one extension to the distal end surface of the at least oneextension; and preparing the corresponding subcutaneous anatomic portionfor the surgical procedure.
 20. The method of claim 19, whereinpreparing the corresponding subcutaneous anatomic portion for thesurgical procedure comprises drilling a hole through the subcutaneousanatomic portion.
 21. The method of claim 19, wherein the subcutaneousanatomic portions are vertebral portions.
 22. The method of claim 19,wherein the subcutaneous anatomic portions are portions of a long bone.23. The method of claim 19, wherein mating the end surface of the atleast one extension to the corresponding subcutaneous anatomic portion,includes telescopically moving the at least one extension to thesubcutaneous anatomic portion.
 24. The method of claim 19, whereinmating the end surface of the at least one extension to thecorresponding subcutaneous anatomic portion includes pivoting the atleast one extension toward the subcutaneous anatomic portion.